Revert of Storing raw audio sink for default audio track.

webrtc/voice_engine/channel_proxy.cc

Index: webrtc/voice_engine/channel_proxy.cc
diff --git a/webrtc/voice_engine/channel_proxy.cc b/webrtc/voice_engine/channel_proxy.cc
index 711f2abd03b0723c913dcdf1329cafd559d49c66..f54c81ec47265f0de194c09f60fa390f25679097 100644
--- a/webrtc/voice_engine/channel_proxy.cc
+++ b/webrtc/voice_engine/channel_proxy.cc
@@ -139,9 +139,9 @@
       channel()->SendTelephoneEventOutband(event, duration_ms, 10, false) == 0;
 }
 
-void ChannelProxy::SetSink(const rtc::scoped_refptr<AudioSinkInterface>& sink) {
+void ChannelProxy::SetSink(rtc::scoped_ptr<AudioSinkInterface> sink) {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
-  channel()->SetSink(sink);
+  channel()->SetSink(std::move(sink));
 }
 
 Channel* ChannelProxy::channel() const {